This invention relates to prostheses in general, and specifically to a construction which permits the attachment of a prosthetic device having a relatively flat surface to the exterior of a prosthetic pylon which has a generally curvilinear exterior.
It is well known in the prosthetic arts, and particularly in the prosthetic leg art, to provide a cylindrical tubular pylon between a wearer's stump and another prosthetic device, such as a prosthetic foot. Such pylons provide a strong, lightweight extension structure between the stump and the other prostheses, which structure may typically be cut to a desirable length for a particular wearer.
Although other pylon configurations could certainly be utilized for this purpose, the cylindrical tubular pylon has numerous desirable characteristics and has therefore become the configuration of choice among many prosthetists and amputees. For example, although prosthetists could utilize solid pylons or pylons having a square or rectangular cross-section or otherwise providing a relatively flat attachment surface for other prosthetic devices, such other pylons typically are not as strong and lightweight as a cylindrical tubular pylon. Moreover, a cylindrical tubular pylon may be relatively less expensive to manufacture than pylons having more complex cross-sectional configurations or requiring more material.
Unfortunately, many of the aforesaid other prosthetic devices which would otherwise be useful in combination with the abovedescribed cylindrical tubular pylons, are not readily usable therewith because they do not have an attachment surface which conforms to the curved exterior of the pylon. Due to considerations of manufacture and/or performance, such other prosthetic devices commonly include relatively flat attachment surfaces for operable attachment to the wearer, whether or not a intermediate pylon is utilized. Thus, in order to be usable with such pylons, these other prosthetic devices must be specifically designed to include special attachment structures and/or configurations which permit attachment to the pylons.
The special designs and modifications of the prior art are not without drawbacks. For example, any such special attachment structure typically adds to the cost of manufacture of the prosthesis. In certain cases, these attachment structures are fairly bulky, weighty, and complex, because the attachment of the aforesaid other prosthetic devices to the pylon must be reliable and secure to prevent undesirable movement between the pylon and the other prosthetic device. Perhaps more importantly, the structures and configurations necessary to permit attachment to the pylons may detrimentally affect the performance of the prosthesis and/or limit the range of wearers who could otherwise benefit from its use.
Exemplary of such design accommodations is the configuration illustrated in FIG. 1 hereto, in which a foot prosthesis A is operatively attached to a tubular cylindrical pylon B through the incorporation of a curvilinear section C and the provision of an attachment mechanism D. As shown in FIG. 1, the combination of the curvilinear section C, its attachment section C.sub.1, the attachment mechanism D, and its attachment section D.sub.1 permits the relatively flat structure C.sub.1 to be operatively retained adjacent the relatively flat bottom of the tube B. Such a structure involves a complexity and expense, and includes performance limitations, which are less than optimum.
Moreover, such a structure requires a substantial clearance beneath the pylon tube B in order to accommodate the components A, C, C.sub.1, D and D.sub.1 thereby limiting the range of amputees who may be served by such a construction.